Achronix Speedster22i 10G/40G/100G Ethernet - Manual (Page 56)

56 UG029, September 6, 2013
control bit has been set the AN_XNP
registers become writeable.
When NextPage control is disabled
(bit13=0), a so-called null-next-page is
automatically set and will be returned to
the remote device for any next page
exchanges requested by the remote.
3
Wait for base
page exchange
completion
KXAN_STATUS
When the Page Received (bit6) is set the
base page exchange has completed.
The remote device's abilities are then
available in the KXAN_REM_ABILITY
registers.
Note: If the remote device is not capable
of autonegotiation the flow will be stuck in
this state. A timeout should be
implemented to exit autonegotiation if no
reaction is found.
4
(opt)
Perform next
page
exchanges
AN_XNP_0..2
KXAN_STATUS
If required to exchange next page
messages, this can be performed after
the base page exchange has completed.
Otherwise this step is skipped.
A write to the AN_XNP2 register forwards
the information to the autonegotiation
statemachine (i.e. sets
mr_next_page_loaded flag), hence must
be written after AN_XNP0,1.
The Page Received (bit6) status register
bit will now indicate whenever a next
page message has been exchanged and
the next page message's Toggle and Ack
bits are used to perform next page
handshaking (AN_XNP/LP_AN_XNP).
5
Configure PCS
Layers
BP_ETH_STATUS
ACT_CTL_SEG
MODE_CTL_SEG
Now the PCS layers need to be enabled
as indicated by the the remote device's
ability received (KXAN_REM_ABILITY)
and resolved as indicated in
BP_ETH_STATUS.
Note: if the remote device continues to
send next-page messages (even if the
local devices has no or no more next
pages to send), the BP_ETH_STATUS
will not be updated until all next-page
exchanges are completed (i.e. not before
statemachine enters AN_GOOD_CHECK
state). The BP_ETH_STATUS has none
of the technology bits set as long as page
exchanges are ongoing.
See 0, Core Configuration Registers for
details on configuring the modes.
6
Reset PCS
Layers
PCS_CONTROL
If the PCS layer configurations are
changed a soft-reset should be
performed after enabling it.
7
Wait for
autonegotiation
completion
KXAN_STATUS
Once the correct PCS layers (and
optional link training) are configured, the
Autonegotiation function will wait for a
proper link and indicate completion when
the link is up.